3.5.2.5.17 Bessel_k1

Definition:

K1 = bessel\_k1(x) evaluates an approximation to the modified Bessel function of the second kind,K_1\left( x\right) . The function is based on Chebyshev expansions.

For more information please review the s18adc function in the NAG document.


Parameters:

x (input, double)
The argument x of the function. Constraint: x> 0.0.
i1 (output, double)
Approximation of the modified Bessel function of the second kind.